Riveting-machine.



W. -T. SEARS.

RIVETING MACHINE.

APPLICATION FILED APR. 7. 1906.

Patented Nov. 24, 1908.

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W. T. SEARS. RIVETING MACHINE. ATPLIOATION FILED APR. 7. 1906.

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WILLARD T. SEARS, OF PHILADELPHIA, PENNSYLVANIA, ASSI GNOR TO N ILES-BEMENT-POND COMPANY, OF JERSEY CITY, NEW JERSEY,

A CORPORATION OF NEW JERSEY.

RIVE TING-MACHINE no. cos, 109.

Specification of Letters Patent.

Patented Nov. 24, 1908.

Application filed April 7-, 1906. Serial No. 310,497.

substantially uniform pressure to be exerted by said head upon a rivet operated on throughout a relatively large part of the latter portion of its stroke.

It is further desired that the above arrangement of mechanism shall be of such a nature that the riveting head shall during the central part of its stroke exert upon a rivet a pressure which increases with substantial uniformity for each unit of movement of said head, such increase of pressure following to some extent the resistance curve of the rivet being upset. I further desire to provide a machine capable of securing the above noted ends, which shall have comparatively few parts and which shall include a device for giving audible indication when the riveting head is in that ortion of its stroke in which it exerts a su tantiallyuniform pressure.

These objects I attain as hereinafter set forth, reference being had to the accompanying drawings, in which:

igure 1, is an elevation, partly in vertical section, illustrating the preferred construction of a machine embod my invention; Fig. 2, is a front elevation of the machine shown in Fig. 1,and Fig. 3, is a curve illustrating the variation of pressure exerted by the plunger at different points of its stroke.

In order to cause the riveting head to exert a substantially uniform pressure during the last portion of its stroke, I attach the connecting rod of the engine or motor for operating the riveter, to two sets of links of approximately the same length. Two of these links are pivoted to opposite sides of the riveter frame, while the other is pivoted offset or placed to one side of the line of movement of the ivot of the third link.

Inthe above rawings, A represents the frame of a riveting machine embodying my invention, which frame is substantially of U-shapcd form having the customary lower 'die a and a portion serving as a guideway for the riveting head or plunger B. This latter has threaded into its lower end a screw carrying the second riveting die I).

, Mounted upon the frame of the machine in any suitable manner, is an engine cylinder C having a piston 0 provided with a connecting rod 0. This connecting rod at its outer end is pivotally'attached to a pair of links 6; one, on each side of the machine, and

these links are in turn pivoted to the frame of the machine;

Pivoted to the riveting head and also connected to the rod 0 and links Z) at or adjacent to their point of pivotal connection is a third link 5 and it is to be noted that the line of the pivots between the said links 5 and the frame, is to one side or is offset from the line of movement of the pivot between said link 72 and the riveting head.

It will be seen that the piston c of the engine has a forwardly projecting portion 0 which cooperates with one head of the engine cylinder in such manner that the area. of thepiston exposed to motive fluid is much greater on one side than on the other. ably guided in this forwardly extended portion of the piston is a rod d carrying on one end a valve 01' designed to fit a suitable seat in an opening through the piston c.

A spring 0 normally tends to kee this valve on its seat-aiid the rod 03 exten s to a point adjacent to the end of the piston extension in such manner as'to be engaged by a cam Z) on the upper end of the link 6 as long as the latter occupies that portion of its path of motion corresponding to the latter part of the stroke of the riveting head. When so engaged by the cam 12*, the rod 01 is moved longitudinally against the action of Suit its spring a to open the valve 03 and permit foreign matter from the-riveting head, while this is being moved in its guides. This particular construction is not illustrated or described in detail in the present case, since it forms the subject matter of an application for U. S. patent filed by me under date of March 17 1906, Serial No. 306,633.

When the riveting head is in its elevated position the piston and links connected thereto occupy the positions illustrated in dotted lines in Fig. 1. When fluid is admitted to the cylinder and the piston is moved to cause the riveting head to make an operative stroke, the various parts are so actuated that at the end of such stroke they occupy the positions shown in full lines. Since, however, the arrangement of links and connecting rod is such that the pivot between the link 6 and the riveting head can never get in line with the pivot between the links I) and the frame A, the pressure exerted by the riveting head throughout its stroke will vary in a definite manner, as indicated by the curve shown in Fig. 3. In said figure each space measured along the horizontal line X represents one unit of movement of the riveting head, while the distances vertically above said line represent pounds per square inch of pressure exerted by the said head.

For the first portion of the stroke of the riveting head there is a comparatively gradual increase in pressure, while for the central portion of the stroke this increase is substantially uniform for each unit of movement of said head, it having been found by experiment to closely follow the curve of resistance of the rivet during the upsettin operation. Throughout the last portion 0 the stroke the pressure varies but very little or is substantially constant, even though it will be noted that said riveting head advances through a considerable distance.

Hitherto it has been found necessary to adjust the position of the die 6 in the riveting head whenever there was an eighth of an inch variation in the thickness of material operated on, while with the arrangement above described I have found that a variation in thickness of three-fourths of an inch is permissible without the necessity for such ad uStment.

In order that the operator may know the part of the stroke occupied by the riveting head, or may know when said head is in that portion of the stroke during which it exerts a substantially uniform pressure when the links or top part of the machine are not in view, I have so arranged the valve d, the cam Z2, and rod d, that said valve will be held open by the cam during that part of the stroke of the riveting head in which its pressure on. the work is substantially constant:the noise caused by the escape of motive f uid giving audible indication of the existence of this fact.

I claim as my invention:

'1. The combination of a frame, a slidable head, an engine having a piston, a connecting rod therefor, with two links of substantially equal length connected together and also to the connecting rod, said links being respectively pivoted to the head and to the frame and having their pivots so placed that the plane of movement of the pivot between the head and one link is to one side of the line of the pivot between the other link and the frame, substantially as described.

2. The combination in a riveting machine of a riveting head and mechanism including a cylinder, a piston mounted therein, links connected to the piston and constructed to cause said head to exert a substantially uniform pressure on a piece of work during the latter part of the stroke of said head, with an alarm device actuated by a portion of said mechanism and arranged to permit the escape of fluid from the cylinder when the links occupy predetermined positions.

3. The combination in a riveting machine having a slidable head, of a link pivoted to the head substantially in the center line thereof, a pair of links pivoted to the first link and also to the frame, the pivots between the said pair of links and the frame being placed so that their line does not intersect the center line of the head, a connecting rod attached to the links, means operative on the rod for actuating the machine, a cam on one of the links, a source of fluid under pressure, and a valve in communication with the source of fluid u der pressure and placed to be actuated by said cam for permitting escape of said fluid when the rivet ing head is in the latter part of its stroke,

substantially as described.

a. The combination in a riveting machine of a frame, a sliding head thereon, an engine mounted on the frame, a'piston for said engine, a connecting rod for the piston, a link pivoted to the riveting head in substantially the center line thereof, a pair of links pivoted to said first link and having pivots connecting them to the frame, said latter pivots extending in a line to one side of the center line of the riveting head and said connecting rod being attached to said links, a valve in the piston, with a valve rod connected to said valve and extending so as to be engaged by certain of the mechanism and caused to open the valve when the riveting head is in the latter portion of its stroke, substantially as described.

5. The combination in a riveting machine of a frame, a sliding riveting head, a motor for actuating said head, and mechanism connecting-said motor and the head, said mechanism consisting of a connecting rod actuated. by the motor and two sets of links of substantially equal length pivoted to each other and to the connecting rod, said sets of links being also respectively pivoted to the In testimony whereof, I have signed my head and to the frame, and the, length of the name to this specification, in the presence of links pivoted to the frame being shorter two subscribing witnesses.

than the distance from the center line of the WILLARD .T. SEARS. 5 head to the pivot between said-links and the j Witnesses: I

frame plus the length of the other set of WILLIAM. E. BRADLEY,

links, substantially as described. 7 'Jos. H. KLEIN. 

